This invention relates generally to computed tomographic (CT) image generation, and more particularly to methods and apparatus for view weighting of CT image data.
Scan data correction plays an important role in the improvement of image quality. The final step of one scan data correction (SDC) process is a view weighting process and often is referred to as SDC-post.
At least one known view weighting process calculates the weights in real time, i.e., during the view weighting process. The performance of this known view weighting process is less than desirable, because calculating the weights requires too much time. Then, because the view weighting process is too slow, the whole image reconstruction process also is too slow. For example, the image reconstruction time exceeds 0.5. seconds for most modes of a four-slice scanner. The image reconstruction time is even greater where the known view weighting process is applied for an eight-slice scanner. Furthermore, the known z-smoothing module is blended into individual view weighting algorithms. Such blending not only complicates the software implementation, but sometimes can result in an incorrect z-smoothing mode.
In one aspect, a method is provided for generating computed tomographic (CT) images. The method includes generating a plurality of projection data, calculating a plurality of base weights using the projection data, storing the base weights in a memory, and applying a z-smoothing module to the base weights to determine a plurality of final weights.
In another aspect, a computer is provided for determining and storing a plurality of weights for each series of images to be reconstructed. In one embodiment, the computer includes a plurality of processors operating in parallel. The computer is programmed to generate a plurality of projection data, to calculate a plurality of base weights using the projection data, to store the base weights in a memory, and to apply a z-smoothing module to the base weights to determine a plurality of final weights.
In a further aspect, a computer-readable medium is provided that instructs a computer to determine and store a plurality of weights for each series of images to be reconstructed. The computer-readable medium instructs the computer to generate a plurality of projection data, to calculate a plurality of base weights using the projection data, to store the base weights in a memory, and to apply a z-smoothing module to the base weights to determine a plurality of final weights.